United States patent application Ser. No. 08/068519, filed 27 May 1993, and now U.S. Pat. No. 5,348,345, assigned to the assignee of this invention, describes a motor vehicle steering system including a pair of variable length shaft assemblies each having a tubular outer shaft of non-circular cross section, a solid inner shaft of corresponding non-circular cross section telescoped inside of the outer shaft, a cavity in the inner shaft defining a spring chamber within the telescopic overlap of the outer shaft, an arched leaf spring in the spring chamber eliminating lateral clearance between the inner and outer shafts, and an in situ injection molded monolithic plastic block in the spring chamber capturing the zero clearance relationship between the inner and the outer shafts and encasing the leaf spring. The plastic block has a low coefficient of friction for minimizing resistance to relative telescopic movement between the inner and the outer shafts. The plastic encased leaf spring has an exposed side slidably engaging the outer shaft and defining a wear plate on the plastic block for maximizing durability. A variable length shaft assembly according to this invention is a novel alternative to the shaft assemblies described in the aforesaid U.S. patent application Ser. No. 08/068519.